import os
import subprocess

def have_needed_diff_support():
    if not os.path.exists('/usr/bin/diff'):
        return False

    ld_cmd = subprocess.Popen(
        ['/usr/bin/diff', '--help'], stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT, env={'LANG': 'C'})
    ld_out = ld_cmd.stdout.read().decode()
    ld_cmd.wait()

    return '-line-format' in ld_out

if not have_needed_diff_support():
  config.unsupported = True
